Computational Fluid Dynamics-Based Design Optimization
CHALLENGE - A ventricular assist device (VAD) is a mechanical device attached to the human heart and vessels as an aid for patients with heart failure, its most complex component being the blood pump. This device can be improved in terms of efficiency and hemolysis, for reducing the cost of existing systems and for increasing robustness and lifetime of the blood pumps. A validated simulation tool that allows computer-based system optimization in addition to the standard trial-and-error development approach is chosen. Here an Archimedes screw pump with guide vanes is considered, as it has a higher pressure head compared with a classical axial pump with the same diameter.
SOLUTION - The method combines the advantages of the established pump design theory with modern computer-aided, computational fluid dynamics CFD-based design optimization (CFD-O) relying on evolutionary algorithms and computational fluid dynamics. It is implemented by coupling the commercial optimization tool modeFRONTIER 4.0 with the commercial CFD package ANSYS CFX 14. Pump hydraulic efficiency is adopted as the primary optimization objective, whereas hemolysis may also be integrated as an additional, concurrent objective
BENEFITS - Results obtained in this study demonstrate that the developed tool is able to meet the objectives. The resulting level of hemolysis can be numerically assessed for the optimal design, as hemolysis is an issue of overwhelming importance for blood pumps. At the end, the very best design showed an efficiency of 65.3%, corresponding to a relative improvement of 25%.